Given the enhanced images produced by the trained neural networks, the existing method can be directly applied to compute the binary maps, such as Otsu [1]} which is very simple and efficient.
Fig. REF  shows the performance of the Otsu's results based on the enhanced images produced by the proposed RR and SR methods with different iterations on the DIBCO 2011 data set.
From the figure we can see that the trained neural network can enhance the document iteratively and the performance is dramatically increasing at the first three iterations.
The performance is slightly better with more iterations.
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